Decoding Five Common Denial Codes in a Medical Practice

<span style="font-size: 18px;">1 – Denial Code CO 11 – Diagnosis Inconsistent with Procedure </span>

It’s not uncommon to see a denial that says the diagnosis coded was inconsistent with the procedure that was coded in the claim. The diagnosis code is the description of the medical condition, and it must be relevant and consistent with the procedure or services that were provided to the patient.

In many cases, denial code CO 11 occurs because of a simple mistake in coding, and the wrong diagnosis code was used. That’s the first thing to check if you get this type of denial. Double-check with the coding department and the patient’s record to ensure there wasn’t a typo or to ensure a diagnosis wasn’t left out accidentally. If there were an error here, you'd need to correct the claim, and then resubmit it as a corrected claim.

If there was no error but you believe that the denial is in error, then you have the option to appeal the claim and provide medical records that back up the medical necessity of the procedure for this patient’s diagnosis.

2 – Denial Code CO 27 – Expenses Incurred After the Patient’s Coverage was Terminated

Denial Code CO 27 occurs when expenses were incurred after the patient’s coverage had been terminated, meaning that your practice provided health care services to a patient after their insurance policy’s termination. Your main goal should be to prevent these types of denials because they’re hard to fight. This means verifying your patients’ insurance benefits before you render services, so your office is alerted as to whether your patient’s insurance coverage has been terminated or is still active. Front office staff should be verifying insurance for every visit, which helps you either get the most up-to-date insurance information or determine that the individual is a self-pay patient.

If you do have a denial code CO 27 occur, double-check to see when the termination date of the policy was. Then, you can check to see if the patient had any other active insurance at the time you provided services. If not, then you’ll need to bill the patient directly.

3 – Denial Code CO 22 – Coordination of Benefits

When patients have multiple payers, coordination of benefits are rules that decide which payer is the primary, secondary, and tertiary insurance to make sure that the correct payers pay and that duplication of payments doesn’t occur. When claims are filed, they must be submitted to the primary insurance first. Then the balance is submitted to the patient’s secondary and tertiary insurances as needed to prevent denial code CO 22. Some of the common reasons that a coordination of benefit denial occurs include:

A missing estimate of benefits
Another insurance is considered the primary
The member hasn’t updated the insurer with their additional insurance information

When this type of denial occurs, your first step should be to check eligibility and determine which of their insurances is their primary one. Then you’ll know better how to submit the claim to the correct insurer. In some cases, this may occur because the payers are confused about which insurance company is primary, secondary, etc. This means the member will need to be notified and will need to update the payers, and then the coordination of benefits can be updated, and the claim resubmitted as necessary.

4 – Denial Code CO 29 – The Time Limit for Filing Already Expired

All payers have timely filing limits and expect that claims will be submitted within the time limit. When claims are not submitted during this time frame, they are denied with denial code CO 29 for filing a claim after the time limit expired. Since you’re likely working with a variety of insurance carriers, make sure that you’re aware of each of their timely filing deadlines, since they can vary. A few examples of common timeline filing deadlines include:

Aetna – Unless exceptions or state law applies
- Hospitals have a year after service to submit the claim
- Physicians have 90 days after the service date to submit the claim
Cigna – Unless exceptions or state law applies
- Out of network providers have 180 days after the service date to submit the claim
- Participating providers have 90 days after the service date to submit a claim
TRICARE – Claims must be submitted within a year after the service date
United Health Care – Provider agreements contain the specified timeline filing limits

5 – Denial Code CO 167 – Diagnosis is Not Covered

Last, we have denial code CO 167, which is used when the payer does not cover the diagnosis or diagnoses. If you encounter this denial code, you’ll want to review the diagnosis codes within the claim. It may help to contact the payer to determine which code they’re saying is not covered, if you submitted multiple diagnosis codes. Then you can decide if another diagnosis code or multiple diagnosis codes should have been used instead. Ensure the diagnosis codes have been corrected and then resubmit the claim as a corrected claim, or you can bill the patient for the services or procedures.